And that usually breaks, as another reply said, when the manager of the two people delegates responsibility for the problem getting solved to one of those two people instead of keeping it for themselves.

If you have a boss who cares whether the task gets done, you can’t make excuses about how it violates your moat to have to do it. Shut up and help your coworker. Now. Or you’re on PIP.

The coworker who isn’t getting useful collaboration gets blamed for their soft skills, when it’s the boss’s soft skills that should have reigned over both.